1. Field of the Invention
The present invention relates to a safety needle assembly with a pivoting shield that is activated during a standard sequence of operation of a medical procedure and, more particularly, relates to a needle and hub assembly having a pivoting shield that is passively pivoted to a shielding position when a sampling tube is inserted within a needle holder.
2. Description of Related Art
An evacuated collection tube, needle cannula (generally a double ended needle cannula) and needle holder are commonly used by a doctor, phlebotomist, or nurse to draw a sample of body fluid from a patient in a hospital or doctor's office for diagnostic testing. During the use of such a collection needle assembly, the distal end of the needle cannula in the needle holder is inserted in a vein of the patient. The evacuated collection tube is then inserted into the proximal end of the needle holder until a needle (the proximal end of a double ended needle cannula) within the needle holder pierces a closure on the end of the tube. The vacuum in the tube then draws a body fluid sample from the patient through the needle cannula and into the tube. After the collection process is complete the needle cannula is removed from the vein and disposed of.
Because of the great concern that users of such needles may be contaminated with the blood of a patient by accidental sticks from the contaminated needle, it is preferable to cover the contaminated needle as soon as it is removed from the vein. For this reason, many developments have been made to provide means for covering the contaminated needle, once it is removed from the patient. These devices usually involve some sort of shield arrangement that moves in place over the contaminated needle once it has been removed from the patient. However, these shield arrangements typically require the use of one or two hands to perform the operation of moving the shield over the contaminated needle, which is a hindrance to the user.
U.S. Pat. Nos. 5,718,239 and 5,893,845 provide safety needle assemblies incorporating a telescoping shield that extends over the distal end of the needle cannula when released by an actuator that is triggered during a standard sequence of operation of a medical procedure. In particular, when the closure or stopper on the collection tube is pierced by the proximal end of the needle cannula, an actuator is triggered to cause the telescoping shield to extend to contact the skin of a patient. Then, when the needle end of the cannula is removed from the patient the telescoping shield continues to extend to a fully extended and locked position over the distal end of the needle cannula, thereby rendering the needle assembly safe and preventing needle stick injuries. While such assemblies provide effective needle shielding techniques, they involve complex mechanisms for activation, and deployment of the telescoping shield may disrupt the patient.
A number of devices incorporate a pivoting shield assembly in which the shield can be pivoted away from the needle during use and pivoted about the needle after use for protection from the used needle. U.S. Pat. No. 5,188,611 discloses a reusable safety needle arrangement having a collar for engaging a needle and a slotted longitudinal shield which is attached to the collar at a hinge for pivoting over the needle. The arrangement includes a locking mechanism for locking the shield over the needle, which a locking mechanism is provided through a set of flanges on the shield which grip a set of complementary catches on the collar. U.S. Pat. No. 6,298,541 discloses a safety shield assembly for a double-ended needle for blood collection procedures with a pivoting shield attached to the needle hub through a collar. The hub includes threads for engaging a conventional needle holder such as that used with the VACUTAINER™ brand of blood collection assemblies sold by Becton, Dickinson and Company. While such shielding assemblies are effective, they require manual operation by the user in order to achieve effective shielding of the needle.
There is a need in the art for a safety assembly, which is automatically activated during the normal procedure used during blood collection and which does not involve a complex activation mechanism.